VELCO uses herbicides, surfactants, drift retardants and other additives to control tree growth in ROWs under transmission lines, to keep trees from touching or falling on the lines, and to allow for other maintenance activities. In forested and forest wetland areas, trees that grow above 15 feet are cut and the stumps are sprayed with herbicides to stop them from growing new sprouts. This report details the chemicals VELCO would use on the proposed 115 kv line from New Haven to South Burlington. Such chemicals have not been used on this right-of-way for 15 years.
VERMONT ELECTRIC POWER COMPANYS
NORTHWEST RELIABILITY PROJECT,
WEED MANAGEMENT HERBICIDES
PUBLIC SERVICE BOARD
Environmental Researcher and Advocate
Charlotte Conservation Commission
Charlotte Town Committee on VELCO
December 20, 2003
INTRODUCTION / ABSTRACT
The Northwest Reliability Project (NRP) proposed in PSB Docket 6860 by Vermont Electric Power Company (VELCO) would replace the approximately twenty-six (26) miles of Green Mountain Powers 34 kV line from New Haven to South Burlington with a much wider (up to 150ft) right-of-way (ROW), taller poles and roughly 3 times the voltage.
GMP has not used herbicides for weed control (except at substations) on their ROW for about fifteen years. If VELCO is given jurisdiction over the ROW from New Haven to South Burlington through the Public Service Board process, they would very likely institute a vegetation management that includes the use of several herbicides and additives, or adjuvants. The expansion and use of that ROW by VELCO through significant natural communities with high public value, and through residential communities and agricultural lands means a significant increase in herbicide use with accompanying risks for the integrity of these natural communities, for water quality, and for long-term public health.
Because of the increased herbicide use resulting from VELCOs NRP, this report discusses the potential undue adverse impacts of herbicides as they relate to the requirements for a Certificate of Public Good, stated in 30 VSA sec.248 (b) (5), particularly in regard to public health, water resources and Charlottes significant natural communities. The report examines relevant bodies of Vermont law, PSB rules, sample permit language, and wetland policy in relation to herbicides. Discrepancies between these documents or policies and VELCOs expert testimony regarding herbicides and wetlands raise concern about how our natural communities, water and air quality can be protected from adverse effects of herbicides and herbicide/additive mixtures.
Each herbicide requested by VELCO for use in its 2003 Permit and ROW vegetation management plan is discussed in regard to environmental fate, effects on wildlife and risks for public health. Additives or adjuvants (not listed in VELCOs ROW Management Plan) are discussed to the extent that information is available about their fate and adverse effects. Inerts, synergism, environmental fate, and chemical sensitivity are covered, where applicable, in context of the discussion of the particular herbicides and additives.
Finally, we offer a viable alternative method for weed control on utility ROWs so that the risks of adverse impacts of herbicides and chemical additives on the natural environment and on public health can be avoided.
Vermont Law pertaining to pesticides
Velcos reason for herbicide use
Potential conflict between 6 VSA 1102 and Velcos proposed NRP
Vermont Law pertaining to Utilities, Environment and Public Health
Charlottes Significant Natural Communities
Permit process for use of pesticides by utilities
Permit language contrasted with VELCOs expert testimony
Agency of Natural Resources policy re wetlands and herbicides
Public Service Board Rules on herbicides
Herbicides Used on VELCO ROWs
Fosamine Ammonium (Krenite UT)
Metsulfuron Methyl (Escort)
Triclopyr (Garlon 4)
Surfactants, Drift Retardants, other adjuvants listed in ROW permit
Alternatives for cut stump sprout control on ROWs
In the adjourned session of 1969, Act 273 established the Vermont Pesticide Advisory Council (VPAC) within the Department of Agriculture and stipulated the regulation of economic poisons. The introductory language of Act 273 reads as follows:
It is essential that man and the total environment be preserved and protected insofar as is possible from hazards presented by substances used to control pests. Certain economic poisons may persist in soil and water, accumulate in plant and animal tissues, and may threaten the existence or health of certain forms of life. Control and regulation of the distribution, sale, use and disposal of those economic poisons is necessary to protect the health and welfare of the people and to keep harmless the environment and resources of the State of Vermont. (Vermont. Acts and laws, 1970, p.354)
Incorporated into Title 6, as Chapter 87, section 1102 (d) of Vermont Statutes Annotated and recently amended, this section describes the establishment and functions of VPAC as follows:
4) To suggest programs, policies, and legislation for wise and effective pesticide use that lead to an overall reduction in the use of pesticides in Vermont consistent with sound pest or vegetative management practices .
(7) To recommend benchmarks with respect to the state goal of achieving an overall reduction in the use of pesticides consistent with sound pest or vegetative management practices, and to issue an annual report to the general assembly, detailing the state's progress in reaching those benchmarks and attaining that goal. Benchmarks should take into consideration, but shall not be limited to, the following:
(A) Reducing the amount of acreage where pesticides are used.
(B) Reducing the risks associated with the use of pesticides.
(C) Increasing the acreage managed by means of integrated pest management techniques.
(D) Decreasing, within each level of comparable risk, the quantity of pesticides applied per acre.
(E) Recommendations regarding the implementation of other management practices that result in decreased pesticide use. (emphasis added)
[(6 VSA sec.1102 (d) (4), (7)]
WHY DOES VELCO WANT TO USE HERBICIDES?
Velco uses herbicides, surfactants, drift retardants and other additives to control tree growth in ROWs under transmission lines, to keep trees from touching or falling on the lines, and to allow for other maintenance activities. In forested and forest wetland areas, trees that grow above 15 feet are cut and the stumps are sprayed with herbicides to stop them from growing new sprouts (VELCO, 1999, p.4,7) Herbicides are used to spray foliage of other trees that could grow too tall, and are sprayed on cut stumps within wetland areas, up to 10 or 30 feet of visible water, depending on the herbicide. Petroleum products are sprayed on trunks of trees in winter when herbicides cannot be applied or when choices are made not to cut trees manually (C. Giguere, personal communication, December 9, 2003).
If VPAC is mandated by law to reduce the use of pesticides, can a transmission company creating a large increase in utility ROW be permitted an increase in the use of herbicides, especially in sensitive areas such as wetlands, or near residential neighborhoods? Will non-toxic alternatives for weed control be recommended or allowed as substitution for toxic herbicide/additive mixtures in residential areas, sensitive wildlife habitats and natural communities?
VERMONT LAW PERTAINING TO UTILITIES, ENVIRONMENT, AND PUBLIC HEATH
30 VSA sec. 248 b 5 states that in considering a utility project for a Certificate of Public Good, the Public Service Board must find that the project will not have an undue adverse affect on air and water purity, the natural environment and the public health and safety The Town of Charlotte has spent considerable effort and funds to identify significant natural habitats within the town, some of which happen to lie within the proposed ROW. The Town is very concerned about impacts to these elements of the natural environment, to our water and air, as well as to human health and safety from increased uses of herbicides and additives within the town on the VELCO ROW, which passes through residential areas.
CHARLOTTES SIGNIFICANT NATURAL COMMUNITIES
The Green Mountain Power ROW (proposed VELCO transmission corridor) cuts a north/south line through the Thorp Brook mouth wetland beside the Vermont Railway ROW. This wetland has been recognized as one of the most important natural areas in Charlotte because of the diversity and quality of its natural communities. In addition, Thorp Brook is considered by the Vermont Biodiversity Project to be one of the states best examples of a small stream in the Champlain Valley. The Nature Conservancy has identified the area as a priority for conservation because of its specific natural communities and because it is part of a larger block of land, or matrix block, that has significance within the St.Lawrence-Champlain Valley region (Thompson, E., 2003). The Charlotte Conservation Commission has spent considerable energy and funds on field work in this special ecosystem in order to protect it from adverse impacts by human development. The Kimball Brook mouth ecosystem is included in a current, ongoing study of the whole Thorp/Kimball wetland ecosystem complex and its potential for reclassification to a Class I wetland area.
This wetland area is home to many species of birds including great blue herons, green herons, bitterns, and woodcocks which build their nests at ground level. They are an essential part of this natural community, and must be afforded protection through the protection of their habitat and nontoxic management practices.
THE PERMIT PROCESS
The Vermont Pesticide Advisory Council (VPAC) consists of delegates from the VT Departments of Agriculture, Health, Transportation, Environmental Conservation, Fish and Wildlife, Forests and Parks, UVM Agriculture and Life Sciences, UVM Medical School and two members of the public, one of them with agricultural experience. VPAC reviews permits for pesticides used by golf courses, railroads, highways and utilities, makes recommendations or put restrictions on the permit, and sends the permit application to the Commissioner of Agriculture for approval. VPAC has also discussed criteria for rating the danger of pesticides and for determining use reduction, chronic pesticide contaminants in Lake Champlain, and other pesticide use issues.
PERMIT LANGUAGE CONTRASTED WITH VELCOS EXPERT TESTIMONY
The ROW herbicide permit granted to VELCO in 2003 requires no-spray buffers of 100 ft from private water sources and 200 ft from public water sources. It states that herbicides shall not enter the waters of the State. Cut stump herbicide applications of Accord may be made up to ten (10) feet from waters of the state. All other herbicide applications shall not be applied within 30 feet of waters of the state. (Vermont. Agency of Agriculture, 2003) There is no language in the ROW permit about buffers to protect wetlands during herbicide applications.
In an email from Cary Giguere, Research Assistant to the Vermont Pesticide Advisory Council with the Dept. of Agriculture, the conditions of the ROW herbicide permits in regard to wetlands are explained as follows:
VPAC does not really comment on use in wetlands as a permit condition but uses distance from surface water as the defining buffer characteristic, and because the ANR Wetland Rules state vegetation control along utility rights-of-way using herbicides is an acceptable practice in wetlands, VPAC has asked the utilities to take more notice of when they are operating in a wetland and please take appropriate action but was not able to condition this in a permit .
Cut stump herbicide applications herbicide applications of Accord may be made up to ten (10) feet from waters of the state. All other herbicide applications shall not be applied within 30 feet of waters of the state. (C. Giguere, personal communication, August 20, 2003)
VELCOs expert testimony by Arthur Gilman and Errol Briggs (VELCO, 2003) states that the Velco Vegetation Management Plan (VELCO Exhibit RJ-5) also bans the use of pesticides or herbicides within 50 feet of a stream or in wetlands. (VELCO,2003,p.13 of 38) The cited document does not support this statement. What the VELCO ROW Vegetation Management does say is quoted below. No buffer of 50 feet to wetlands is mentioned.
While wetlands are not specifically mentioned in the VT Pesticide Control Act (6 VSA Chapter 87-Section IV) or in the VT Department of Agriculture herbicide application permits, VELCO uses mechanical methods to control tree species in wetlands. The National Wetlands Inventory Maps are used to identify the location, size and type of wetland areas associated with right-of-ways. It is acknowledged that the NWI maps do not show every wetland or precise locations. Field decisions are made from time to time by the foreman of the crew (generally a forester). Formal wetlands identification training is conducted by a qualified biologist periodically the crew foremen for familiarization and review.
When a herbicide use permit is approved and issued by the VT Department of Agriculture, it contains specific instructions related to protecting the waters of the State. This is done by requiring various widths of buffer zones near streams, rivers, ponds and lakes. These instructions insure that no herbicide applications ever take place in running or standing water. Currently all herbicides that VELCO is permitted to use are labeled for use in wetlands. If the opportunity became available to judiciously use herbicides in wetlands in accordance with specific permitted guidelines, it would be the method of choice by which to minimize adverse effects on wetlands and associated buffer zones. (VELCO, 1999, p.11)
ANR POLICY ON PESTICIDE USE IN WETLANDS BY UTILITIES
Counsel for Vermont Agency of Natural Resources wrote an opinion dated March 8, 1999 that states: a reasonable legal argument can be made that seasonal herbicide application is an allowed use under Vermont Wetland Rules, subsection 6.2 (1), in relation to railroads and utilities, if herbicides are used to maintain existing structures .However, designating an activity as an allowed use is not a determination that the subject activity will not impact wetlands .exemptions to the regulations should be construed as narrowly as possible. (Raubvogel, A., 1999)
PUBLIC SERVICE BOARD RULES
PSB Rules section 3.600 pertaining to maintenance of electric utility ROWs recognize that herbicides raise concerns for landowners and citizens and provide for landowner requests for no-spray areas (3.640), notification of landowners (3.621), and allows utilities to levy a fee on those landowners who request no herbicides at all on transmission lines (3.641), even though other methods may be available for the vegetation management plan (3.631 D). Rule 3.631 J provides for periodically reviewing, evaluating and revising the long-range management plan and is important for its consideration of non-toxic alternatives for weed management as they become available for use. Rule 3.622 concerning the information sheet contains important directives concerning the protection of private water supplies, but appears to apply to distribution lines. The obligation of transmission companies to distribute the information sheet is unclear, as compared to distribution utilities, even though the conditions of treatment by the transmission company are or will become the major concern in many areas.
HERBICIDES AND ADJUVANTS
Fosamine Ammonium (Krenite UT, Krenite S)
Krenite S is a water soluble liquid, containing 4 lbs of active ingredient per gallon. It consists of 41.5% ammonium salt of fosamine [ethyl hydrogen (aminocarbonyl) phosphonate] and 58.5% inert ingredients by weight (DuPont, 1997-2000). Inert ingredients in krenite include tridecyl alcohol (specific chemical identity and CAS number not revealed by manufacturer) and water, the proportions of which are not stated (U.S. Dept. of Energy, 2000).
Krenite is used as an herbicidal brush control agent and a plant growth regulator. The product was introduced in 1974 by Dupont. The active ingredient fosamine ammonium degrades to carbamoylphosphonic acid (CPA), the principal degradate, as well as carboxylphosphonic acid and carbon dioxide. No fate or toxicity data is available for the two degradates (U.S. Dept. of Energy, 2000).
In Vermont Krenite is used in a tank mix with imazapyr (Arsenal), metsulfuron methyl (Escort) and a drift retardant, Thinvert, in a low volume spray from a backpack at a rate of .1 to 3 gallons per acre (C. Giguere, personal communication, September 2, 2003). These products are discussed below. Briefly, Thinvert is a combination surfactant and drift retardant composed of an isoparaffinic hydrocarbon blend and nearly 70% unnamed ingredients including surfactants. The toxicity of such a combination remains untested and unevaluated.
Concern for birds: Effects on bird populations are a significant concern with respect to Krenite. Depending upon the formulation used, birds that nest near (up to 15 ft) or on the ground may experience deformities if eggs are drenched with fosamine ammonium. European researchers found several types of deformities in quail when the eggs were sprayed with 1.0% concentrations of fosamine ammonium, and that the deformities increased noticeably at a 1.5% concentration. The deformities included misshapen heads, beaks, tails, clenched feet, dwarfism, edema in the neck and chest region (Lutz-Ostertag, Y., 1983.) A United States Fish & Wildlife Services researcher found that toxicity was greater to mallard embryos than to bobwhites, and that the effects were mainly severe edema and some stunting. This author found affects only at much higher concentrations than Lutz-Ostertag did, who may have had a formulation containing cholinergic impurities. Hoffman examined the nervous system effects because the formulation might contain one or more components or impurities with cholinergic properties, an indication of toxicity to the nervous system (Hoffman, D., 1988).
Environmental fate: Fosamine ammonium is stable for extended periods in neutral or alkaline water. Microbial degradation is the principal process of breakdown in the soil, and can take four (4) weeks to degrade 45% of applied formulation. In the atmosphere, fosamine ammonium can exist as vapor and as particulates, and in some conditions will be deposited by both dry and wet deposition, with a half-life in the atmosphere of about 8 hours (U.S. National Library of Medicine. HSDB, 1998).
Concern for humans: In reference to short-term exposures, the Hazardous Substances DataBank states that fosamine ammonium is irritating to the eyes, nose, throat, and skin, and that breathing spray or mist should be avoided. A specific review on the clinical effects and treatment of individuals exposed to this agent has not yet been prepared. (U.S. NLM. HSDB, 1998)
Tests of fosamine ammonium on hampster ovary cells showed chromosome aberrations at 16.7 and 33.3 microliters per milliliter. Chromosome breakage was observed at concentrations of Krenite equivalent to 1.4% to 3.2% solutions (U.S.E.P.A., 1995. Case 2355. p.11-12). Chromosomes are structures in the cells that contain hereditary instructions for development. Breakage of chromosomes can lead to congenital disease or malformations in organisms.
Data gaps still exist in relation to this chemical. EPA has not evaluated fosamine ammonium for endocrine disruption or effects on the immune system from low-dose chronic exposure. Neither EPA (U.S.E.P.A. 1995, p.20) nor VT Department of Health (VT. Dept. of Health, 2002) has set drinking water advisory levels for fosamine ammonium, nor will EPA mandate any monitoring of water for this chemical, even though in some conditions it can leach to water and remain in the water for some time. EPA requires no data for post application exposure or re-entry into a treated area (U.S. NLM HSDB, 1998), even though such treatments can take place near residences or areas where citizens may hunt, walk, or pick berries.
Concern for chemically sensitive persons: The potential for Krenite to contain contaminants with cholinergic (toxic to nervous system) capability needs more investigation. In future uses of this herbicide the applicants should observe a buffer of two (2) miles from human dwellings to prevent toxicity to vulnerable populations including chemically sensitive persons, children, those with lowered immune systems or recovering from cancers, or use non-toxic alternatives. The chromosome issue also indicates a caution for humans, especially pregnant women and small children.
Concern for ecosystems: Use of Krenite in significant natural communities should be avoided because threatened and endangered species of plants may be adversely affected if the product is applied directly to the plants during budding and leafing until fall coloration. (U.S. Dept. of Energy, 2000, p.3) Because of the potential for being contaminated with cholinergic compounds, Krenite may be toxic to bird embryos.
Inerts: The inerts in Krenite (58.5% of the formulation) include tridecyl alcohol and water. Tridecyl alcohol, or tridecanol may be hazardous to the environment; special attention should be given to fish. In regard to humans, the substance irritates the eyes and the skin (United States. National Institutes of Occupational Safety and Health, 1998).
Glyphosates chemical name is N-(phosphonomethyl)glycine and is often used in the form of isopropylamine salt of glyphosate. The glyphosate product used by VELCO is Accord, which consists of 41.5% isopropylamine salt of glyphosate and 58.5% other ingredients (Monsanto Co., 2000) which have been identified through a FOIA process as water and FC&C Blue no.1 (Furlow, Calvin, B. 1999).
Glyphosate is a widely marketed broad-spectrum herbicide, appears in several formulations including Roundup, Roundup Ultra, Rodeo, Accord, and has been registered for almost 30 years. On Vermont utility ROWs, glyphosate has 2 principal uses: (a) as Accord Concentrate (53.8% glyphosate) occasionally mixed with a surfactant for cut stumps up to 10 feet from water; (b) in a mix with Escort and Arsenal for a backpack sprayer (C. Giguere, personal communication, September 5, 2003).
Environmental fate: Glyphosates persistence in the soil varies widely, with time required for half of the amount of pesticide applied to break down (half-life) ranging from 3 days in Texas to 141 days in New York. Initial breakdown can occur faster than the degradation of the remaining residues (U.S.E.P.A. EFED, 1993). While glyphosate does bind to sediment and soils, it can also become unbound and continue to move in the soil (Piccolo, A. et al, 1994). The only identified metabolite or degradate of glyphosate is aminomethylphosphonic acid (AMPA), which can reduce liver weight and cause abnormal cell division in the bladders of small mammals (Agriculture Canada, 1991). AMPA is far more stable to photo-degradation than the parent compound, and can be further broken down to formaldehyde (Lund-Hoie, K.& H.O. Friestad, 1986). In one study, glyphosate and AMPA were both still detectable in leaf litter 100 days after an application. A study in Finland found glyphosate and AMPA in reindeer lichens 270 days after application (Mensink, H. & P.Janssen, 1994).
Concerns for plant communities on land: Because of its behavior in soil and ability to drift, glyphosate use holds dangers for plant communities. Researchers have found that glyphosate can drift as much as 130 feet and do harm to sensitive native species (Marrs, R.H. et al, 1993). Glyphosate can do damage to non-target plant species because it moves easily within the plant, damaging even unexposed parts of the plant. Drift of herbicide can affect natural vegetation by damaging sensitive species and thereby altering the structure of the community in the long term. Of four herbicides studied, wild plants were at a much greater risk of damage from glyphosate drift, in amounts as low as .1 micrograms per plant (Breeze, V. et al, 1992). Endangered plant species and viability of plant communities could be jeopardized because glyphosate can prevent calcium uptake by plant roots, increase plants susceptibility to pathogens, and inhibit growth of various soil micro-organisms (Carlisle, S.M. and J.T.Trevors, 1988). Glyphosate treatment made plants more susceptible to colonization of plant roots by pathogens because of complex plant /chemical interactions (Brammall, R.A. and V.J.Higgins, 1988).
Several modes of glyphosates behavior raise concerns for maintaining the integrity of Charlottes sensitive plant communities, including wetlands.
Concerns for aquatic ecosystems: Since glyphosate is the herbicide allowed for use close to water and is used in wetlands, the nontarget dangers of the herbicide in aquatic ecosystems need to be considered. Glyphosate is toxic to tadpoles and to frogs, although Roundup is more toxic than technical grade glyphosate because of the surfactants effects on the gills and skin of amphibians (Bidwell, J.R. and J.R.Gorrie, 1995). The adsorption of glyphosate to suspended clay particles in water can lengthen its persistence in the aquatic systems (Bowner, K.H., 1982) keeping it available to aquatic invertebrates that live in sediment and filter it through their bodies. Glyphosate can act as a nutrient in water because of its phosphate content, even amounts below detectable level, indirectly affecting fish habitat, and can cause mortality to larvae of an aquatic invertebrate species (Austin, A.P.,1991). Concentrations of glyphosate below the detection limit may contain enough glyphosate to be available for adsorption to sediment (Newton, M.et al, 1984). Because glyphosate can drift off-target, bind to sediment and erode into streams, populations of invertebrates such as fresh-water mussels (some listed as Endangered or Threatened in Vermont) in affected streams could face additional risks to their survival.
Concerns for animal life: Glyphosate is directly toxic to some beneficial insects, and can reduce the population of others through habitat reduction (Cox, C., 1998). Populations of voles and shrews were reduced for two to three years in Maine studies (Santillo, D.J., 1989. One researcher found that low chronic doses of glyphosate reduced the ability of rabbits to reproduce successfully because sperm were less viable, either because of the toxicity of glyphosate to cells or because reproductive hormones were disrupted (Yousef, M.I.et al, 1995).
Concerns for humans: Humans are exposed from utility uses through occupational use of glyphosate, via drift or off-target from applications, through contact with contaminated soil, or drinking or bathing in contaminated water. In California where statistics on pesticide-related illness are recorded, glyphosate caused 28 reported systemic and respiratory acute illnesses, and 151 reported skin and eye acute illnesses between 1984 and 1990 (Pease, W.S. et al, 1993, p.8). Most injuries were associated with ground or hand application as well as with mixing and loading (Pease, W.S.et al, 1993, p.18). Other effects of glyphosate on human health include burning of eyes or skin, blurred vision, peeling of skin, nausea, headache, vomiting, numbness, burning of the genitals, and wheezing (California. EPA. DPR. 1993-95).
New research indicates that glyphosate and its formulations cause DNA-damaging activity in the liver and kidney of mice. No significant difference is seen between the active ingredient and its formulation (Bolognesi, C.et al, 1997).
Imazapyr is a nonselective, broad spectrum herbicide of the imidazolinone family and is used principally on rights-of-way in the U.S. On VELCOs ROWs it is used in a mix with glyphosate, metsulfuron methyl and Thinvert, a combination dirift retardant and surfactant described below, or in a mix with fosamine ammonium, metsulfuron methyl and Thinvert (Vermont. Agency of Agriculture. 2003).
Its mode of action in plants is similar to that of the sulfonylureas (see Metsulfuron methyl below), which is to inhibit an enzyme used by plants to synthesize amino acids, the building blocks from which living organisms make proteins. Death of the plant occurs slowly, as much as a month after treatment (Cox, C., 1996).
A common measure of the persistence of a herbicide is the half-life, or the length of time required for half of the applied chemical to break down or move away. Studies based on plant injury as an indicator show longer persistence than those that depend on laboratory analysis (Coffman, C.B. et al, 1993). Half-lives of 21 days to 49 months are indicated in field studies (U.S.E.P.A. OPP, 1984).
Concern for groundwater: Imazapyr has chemical characteristics that indicate it is mobile in soil and likely to contaminate groundwater. It also has high potential for surface water runoff (U.S. Dept. of Energy, Imazapyr, 2000). EPA found that while it has moderate capability for adsorption to soil particles, it has a high potential for desorption, or becoming unbound from soil particles. Researchers found that the breakdown of imazapyr was very slow, and that significant amounts leached to 45cm depth, the deepest extent measured in the study ( Vizantinopoulos, S. and P. Lolos, 1994).
Concerns for plant communities: Imazapyr is a potent herbicide, so that drift of small amounts can harm non-target plants. Concentrations as small as 1/50 the normal agricultural rate (approx. 3-4 qts/acre) reduced potato yields to as little as one-third that of unexposed plants (Eberlein, C.V., M.I. Guttieri, 1994). Drift of such herbicides is a danger to non-target plants in significant natural communities.
The same property that makes imazapyr effective on weed plants in agricultureits ability to penetrate root systems of target plants (Santoro, A. et al, 1999) -- also makes it a danger for non-target plants and a risk for maintaining ecological integrity in sensitive natural communities.
Other effects of imazapyr on non-target plants include increased susceptibility to disease and the disruption of nutrient cycling in the soil. In combination with diuron (a very persistent herbicide applied by VT RR for nearly 20 years, which may have drifted off-target) imazapyr increased the severity of a fungal leaf disease, resulting in a significant decrease in stem growth when trees were exposed to the herbicides (Zhang, Y.C. and J.T.Walker, 1995).
Resistance: Resistance to imazapyr (the ability of plants to tolerate amounts of the chemical that would normally be toxic) is developing, not so much from use of imazapyr, but from the use of sulfonylureas (see metsulfuron methyl below). Since the herbicides have similar modes of action, there is a tendency for cross-resistance to develop from repeated exposure to sulfonylureas (Burnet, M.W.M. et al, 1994).
Concerns for wildlife: There are no studies on the chronic toxicity of imazapyr products to animals (U.S. DOE, 2000, Imazapyr).
Concerns for human health arise partly from one of the breakdown products of imazapyr in soil, quinolinic acid, which is irritating to eyes, the respiratory system and skin (Cox, C., 1996). It is also a neurotoxin which can cause nerve lesions and symptoms similar to Huntingtons Disease (Schwarcz, R.et al, 1983).
Its capacity to drift off-site increases risk to human health, particularly to children, the chemically sensitive and those with lowered immune systems, and relates to more subtle adverse effects on human health. One of those effects involves the complex biochemical system of receptors and hormones in mammals and the potential that exposure to imidazoline-related chemicals could effect or disrupt those processes (Reis, D.J. et al, 1995, p.178,208,216,218,361-2,371). Citizens can be exposed to imazapyr through drift during application, through wind-blown contaminated soil particles, touching treated vegetation, or through imazapyrs potential for leaching to groundwater. Imazapyr is corrosive to the eyes and causes irreversible eye damage (U.S.E.P.A. OPP,1984).
Inert ingredients in Arsenal: Inerts are not chemically inactive, as the word inert implies, but simply unnamed ingredients, and consist of 71.3% of the formulation. The inerts in Arsenal include water, glacial acetic acid, and others claimed confidential (Furlow, C. B., 1999). The term glacial came to be used for the pure acid in either its solid or liquid state. Pure or concentrated acetic acid is very corrosive and can cause painful burns. Acetic acid has many uses in industry, and is used as a fungicide and as a solvent for many organic compounds (Shakhashiri, B.Z, n.d.).
Metsulfuron Methyl (Escort)
Metsulfuron methyl is one of the sulfonylurea class of herbicides which are being used to replace older chemicals. The sulfonylureas (SUs) are potent and used at very low concentrations, that is, _ to 4 ounces per acre per year (DuPont, Escort, 2001-02), as compared to quarts or gallons per acre for other herbicides. VELCOs permit allows use of this herbicide in one of two mixes: one with imazapyr (Arsenal), glyphosate (Accord) and Thinvert; another with fosamine ammonium (Krenite), imazapyr (Arsenal) and Thinvert (VT. Agency of Agriculture, 2003).
Environmental fate: The environmental fate of this herbicide is complex, making it difficult to establish its persistence in the environment. Residues of metsulfuron methyl bound to soil particles can inhibit the growth of plants grown in treated soil for nearly a year (Xu, J. et al, 2002). Metsulfuron methyl contamination of soil or water can cause adverse effects (i.e. reduction in growth) in sensitive plant species; the severity and duration of these effects depends upon rainfall, pH of the water or soil, and amount of organic matter. The persistence of metsulfuron-methyl involves many variables, and soil half-lives ranging from a few days to several months have been reported. In areas with significant rainfall, concentrations of the herbicide that are toxic to non-target plants can remain in the soil as deep as one foot for up to a year. Contamination of surface water at low concentrations is possible in areas receiving 25-50 inches of rain per year (Syracuse Environmental Research Associates, 2000, p.4-14).
Special concern for agricultural crops and non-target plant communities: A major concern about SUs is their ability to harm non-target plants at extremely low concentrations through drift. The manufacturer of EscortDupontstates in their product sheet that This herbicide is injurious to plants at extremely low concentrations. Non-target plants may be adversely affected from drift and run-off. (DuPont, Escort, 2001-02)
As early as 1981, EPAs Environmental Fate and Effects Division (EFED) recommended that sulfonylureas not be registered based upon the environmental fate data which indicated persistence in the environment, potential to leach into groundwater and the potential for drift, with serious damage to non-target plants and crops. A further difficulty at that period (early 1980s) was the lack of technology in laboratories to detect SUs at the low concentrations at which they could do damage in plants. Laboratory sensitivity has been recently increased so that SUs can be detected to very low concentrations. The concern about drift remains.
In 1986 the EFED began a review of non-target phytoxicity (toxicity to plants) data regarding widespread plant injury following use of a sulfonylurea on soybean crops. EPA-sponsored studies in cherry orchards showed that while no visual adverse effects were observed on plants exposed to 1/500th the label rate of chlorsulfuron, cherry yield was reduced significantly by 85%. Seed production of white mustard was adversely affected at 1/10,000 the label rate for chlorsulfuron. These findings show that SUs are unique in their ability to cause significant adverse effects at very low concentrations (Maciorowski, A.F., 1994).
Concern for plant communities: The high toxicity of sulfonylureas to plants at extremely low concentrations and their adverse effects on the ability of plants to set seed (reproduce themselves) make this family of herbicides a high risk for use on VELCO ROWs within significant plant communities in the Thorp/ Kimball Brook wetlands, near agricultural crops, or near homes where citizens grow their own food. Such concerns are based upon documented experience and research.
Concern for agricultural interests: The dangers of sulfonylureas were first understood in the context of widespread damage to agricultural crops from drift of sulfonylureas in other applications, such as railroad right-of-ways. In 1997, crops at a Shoreham, VT organic vegetable and flower farm were largely destroyed by drift of a sulfonylurea herbicide sprayed from the air over a neighbors corn crop; as a result, the VT Dept of Agriculture put a moratorium on the aerial spraying of sulfonylureas. The use of such herbicides near agricultural lands, with possible widespread damage to agricultural crops, brings risks for an important economic base that must be taken seriously by all parties concerned.
Concerns for mammals: According to Duponts own Material Safety Data Sheet on metsulfuron methyl, single exposures of animals to metsulfuron methyl by inhalation caused body weight loss and other nonspecific effects . Repeated oral doses of this herbicide produced decreased body weight gain and decreased liver weights when compared to the control group. Long term administration caused body weight loss. (DuPont, 2003)
Concerns for humans: Researchers have found that chlorpropamide, a sulfonylurea used to treat diabetes, can increase the risk of severe hypoglycemia (imbalance in the bodys ability to metabolize carbohydrates). In addition, laboratory research has demonstrated that this sulfonylurea caused developmental defects and growth retardation at concentrations in ranges similar to normal human therapeutic levels of 30 to 100 micrograms per milliliter. Human studies have shown evidence of chlorpropamide crossing the placenta into the embryo. Sulfonylureas are thought to produce the release of insulin by blocking complex bio-chemical actions which occur in divers organs and systems of the body, such as the heart, the skeleton, and smooth muscle cells and central neurons. The importance of such systems in the development of the embryo are yet to be evaluated. The effects of sulfonylureas on complex bio-chemical processes in the human represent an area of concern, especially since previous studies have demonstrated embryopathic effects of chlorpropamide in laboratory animals and have suggested that this compound may also be teratogenic in humans. ( Smoak, I., 1993)
A study of frogs exposed to sulfonylurea herbicides showed adverse affects upon their ability to transform normally from tadpoles to adult frogs. The thyroid hormonal system is of paramount importance in the maturation of frogs, and the kinds of developmental problems demonstrated by the frogs exposed to sulfonylureas pointed to an inhibition of the thyroid system (Fort, D.J., 1998).
While the exposure route for sulfonylureas differs between laboratory and public exposure, and the transfer of effects from animal to human has not yet been positively established for some effects, the capacity of sulfonylureas to disrupt hormones and other complex bio-chemical processes in mammals, including humans, remains a valid concern.
Inerts comprise 40% of the formulation of Escort, and have been identified in a FOIA process (Furlow, C.B., 1999) as the following (proportions unknown):
--sodium naphthalene sulfonate-formaldehyde condensate
--mixture of sulfate of alkyl carboxylate and sulfonated alkyl naphthalene, sodium salt
Formaldehyde, one constituent in an inert ingredient in metsulfuron methyl, is included by the US EPA in its List 1 of inerts of toxicological concern (Pesticide & Toxic Chemical News July 2, 1998, p.19). EPA has designated formaldehyde as a hazardous air pollutant, water pollutant, and waste constituent, and states that it is reasonably anticipated to be a human carcinogen (U.S.NIEHS. 2001) Low levels of formaldehyde can irritate the nose and throat, and long-term exposure can cause dry, sore throat, inflammation and swelling of the lungs and bronchial tubes. It can cause asthma-like symptoms when workers become sensitized to the chemical. Such sensitivity can occur suddenly even in someone who has tolerated the chemical for some years. After a person becomes sensitized, very low concentrations of the chemical such as those present in manufactured clothing, can trigger severe reactions. Skin contact with formaldehyde can cause blisters, red and dry skin, which worsen with heat and sweat (NYCOSH, 2003)
Naphthalenes major use is in the manufacture of moth balls. Exposure to large amounts of this substance can damage or destroy red blood cells. The effects depend on the dosage, duration, manner of exposure, and whether other chemicals are present. Naphthalene is volatile, evaporating easily, and it binds weakly to soils and sediment. It can remain in the milk of cows exposed to it, and in the eggs of hens exposed to the chemical. (U.S. Agency for Toxic Substances and Disease Registry, 1995)
Polyvinyl pyrrolidone (PP) can cause nasal cavity inflammation, atrophy of the olfactory mechanism, and abnormal increase of cells in the lining of the nose and respiratory system. In humans and experimental animals, PP accumulates in cells of many organs and may cause pulmonary fibrosis (development of fibrous tissue in the lungs) and pneumonia in humans (IARC, 1999)
These are only a few of the inert constituents in Escort herbicide, and one must still consider the toxicity of the mixture of all the inerts combined with the two other herbicides in the tank mix, and their inerts as well as the surfactant/drift retardant Thinvert, an isoparaffinic hydrocarbon blend. No assessment has been made of the human health or environmental effects of such a complex mixture intentionally released to the environment.
Triclopyr (Garlon 4)
Garlon 4 is comprised of 61.6% active ingredient triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid, butoxyethyl ester) and 38.4% inert ingredients, including kerosene. (U.S. Forest Service, 1996) The product also contains petroleum distillates. On VELCOs ROW, Garlon 4 is primarily used alone, in concentrations of .1 to 2 gallons per acre, from a squirt bottle as a treatment on cut stumps to prevent growth of new tree sprouts, and is allowed for use within wetlands up to 30 feet from water. Hy-Grade 1 (petroleum oilsee product discussion below) is occasionally mixed with Garlon 4 for treatment of tree trunks (C.Giguere, personal communication, Sept. 5, 2003).
The following cautionary statements are found in the Specimen Label by Dow AgroSciences for Garlon 4: This pesticide is toxic to fish. Do not apply this pesticide in a way that will contact workers or other persons, either directly or through drift. Applications should be made only when there is little or no hazard from spray drift. (Dow AgroSciences, 1997)
Environmental fate: The environmental fate of triclopyr has raised concern for a number of reasons. Both forms of triclopyr (amine and ester) create an acid form in the soil. This acid and the chief degradate TCP (3,5,6-trichloro-2-pyridinol) are of concern in regard to groundwater. Triclopyr acid is somewhat persistent, with persistence increasing as it reaches deeper soil levels, where there are anaerobic conditions; it is also very mobile. TCP is both mobile and persistent .Due to the environmental fate characteristics of triclopyr acid, the Agency believes this chemical has a potential to leach to groundwater. (U.S.E.P.A.,1998, p.62) Triclopyr tends to be more persistent in forestry sites than in agricultural sites (U.S.E.P.A.,1998, RED, p.58-61). Triclopyr is not strongly adsorbed to soil particles, and adsorbed molecules may later detach into water moving through the soil. The US Forest Service in the Pacific Northwest found detectable residues of triclopyr in soil 477 days after treatment, and that half-lives of the metabolite TCP can range from 8 to 279 days in tests on 15 different soil types (U.S. Forest Service. Northwest Region, 1996) The herbicide has been found by a USGS monitoring program to contaminate streams and rivers: triclopyr was found in 8 of 20 river basins studied. On a more local scale, a USGS study of 10 urban watersheds found triclopyr in 90 % of the sites sampled. (Cox, C., 2000)
Concerns for plant communities: Very small quantities of spray which may not be visible may seriously injure susceptible plants. So warns the product label for Garlon 4 published by Dow AgroSciences (Dow AgroSciences, 1997). Triclopyr is toxic to many broadleaf plants. It may be found at concentrations of 2.4 parts per million (ppm) in berries harvested 6 days after treatment. TCP has been found in roots of plants after treatment (U.S. Forest Service. Northwest Region, 1996).
The ester formulation of triclopyr as used in Garlon 4 poses a greater threat to non-target plants than the amine formulation. Spray drift is a higher risk to non-target plants than run-off in the ground. Endangered plants can be at risk from all uses of either form of triclopyr. EPA found that in relation to drift of triclopyr, only the use on rice at low concentrations did not exceed the Agencys level of concern. In all other registered uses the level of concern for acute risk to non-target plants was exceeded. (U.S.E.P.A. 1998, RED, pp.103-104)
Triclopyr presents risks to the integrity of significant plant communities in other ways. One is by inhibiting the transformation of atmospheric nitrogen to a form that is usable as a nutrient by plants for growth. This herbicide is more potent in reducing this activity than about 70 percent of the 48 pesticides tested. (Pell, M. et al, 1998) Another impact on plant communities is the reduction of diversity of lichens and mosses, which are important parts of forest ecosystems, contributing to nutrient cycling, production of high-quality seedbeds, and maintaining moisture levels in the ecosystem. (Newmaster, S.G.et al, 1999)
Concerns for wildlife: Triclopyr ester (Garlon 4) is toxic to fish, as pointed out in the Dow AgroSciences Specimen Sheet. Sublethal concentrations in water can affect fish behaviour, inducing rapid respiration at the surface of the water, flared gills, and erratic disoriented swimming (Morgan, J.D. et al, 1991).
Concentrations of just over 1 part per million prevented tadpoles of 3 species of frog from reacting with normal avoidance behavior, making them very susceptible to predation. Such a concentration can occur in a treated forest area (Berrill, M. et al, 1994)
An inert ingredient in triclopyr is kerosene, which presents toxicity problems for birds and their ability to reproduce successfully. (see below in inert ingredients)
Concerns for humans: The chief metabolite of triclopyr is TCP, which is also a metabolite of the insecticide chlorpyrifos. TCP can inhibit neurons, or nervous system cells, from undergoing normal growth at concentrations of only .2ppm. Concentrations at this level have been measured in the brains of fetal laboratory animals whose mothers were exposed to pesticides. In addition, the amounts in the fetal brains were between two and four times greater than the amounts in the maternal brain (Hunter, D.L. et al, 1999) Mothers and infants can be exposed to TCP through drift during applications, windblown particles of contaminated soil or using contaminated water.
TCP is very mobile in a variety of soils, is often more persistent than triclopyr itself, and is toxic to soil bacteria and to chicken embryos (Cox, C., 2000)
EPA has not evaluated triclopyr specifically for endocrine disruption, but has not found any effects on the endocrine system in any of the chronic or reproductive toxicity tests done for this compound (Federal Register, 1998)
Inerts in triclopyr: Except for acute toxicology testing of Garlon 4, All toxicology tests required by EPA for registration were conducted with the active ingredient triclopyr alone, not the whole formulation that includes the inert ingredients. The inerts in Garlon 4 include the following, as divulged through a FOIA process (Furlow, C.B., 1999):
1. Kerosene could be toxic to bird embryos in the egg stage; less than 50 micrograms per egg can have lethal effects. The petroleum product can act as a vehicle to help the formulation penetrate the shell, block oxygen infiltration to the embryo, and cause deformities and death. The presence of heavy metals in petroleum products can be toxic as well (Hoffman, D., 1990).
In humans, kerosene causes severe eye irritation and is irritating to the upper respiratory tract. Inhalation of kerosene causes fatigue, headache, and dizziness, and can also cause disorientation and drowsiness (Cox, C., 2000).
2. Ethoxylated sorbitan monooleate can be harmful by inhalation, ingestion, or skin absorption, may cause eye irritation and skin irritation with risk of irreversible effects, is a possible carcinogen; the chemical, physical and toxicological properties have not been thoroughly investigated. (Anatrace, Inc. MSDS) Such compounds contain allergens before they are exposed to air (oxygen) and new allergens are formed upon their exposure to air (Bergh, M., 1999).
Acetaldehyde has been detected in ethoxylated sorbitan monooleate (Tween 80) and has allergenic and sensitization activity in humans (Bergh, M., 1999).
3. Dodecylbenzenesulfonic acid (B-DBS) is a compound used as a detergent or surfactant. The environmental fate of such detergent formulations is of concern because certain classes of them are persistent in the environment. Understanding their breakdown process is important for solving water pollution problems. The compound (B-DBS) may be partly degraded by bacteria, but most of the degradation is carried out by a new, complex pathway which must be further analyzed (Campos-Garcia, J.et al, 1999).
SURFACTANTS, DRIFT RETARDANTS, PENETRANTS
in VELCOs Vermont Permit Application
This non-ionic surfactant is designed to quickly wet and spread a more uniform spray deposit over leaf and stem surfaces. It is composed of a blend of 90% alkyl aryl polyoxylkane ethers, free fatty acids, and also contains isopropyl alcohol (Franz, J.E. et al, 1997, p.195).
The specimen sheet for INDUCE states that the addition of an adjuvant to some pesticides or pesticide tank mix combinations may cause phytotoxicity [toxicity for plants] to the foliage and/or fruit of susceptible crops. The product is generally used at 1 to 4 pints per 100 gallons of spray mix (Helena Chemical Co., Induce, 2001a).
Exposure to INDUCE can cause nasal and respiratory irritation. Chronic skin exposure can lead to dermatitis with drying and cracking of the skin. The product is considered a moderate skin irritant (Helena Chemical Col, Induce, 1996).
Kinetic is a silicone-based surfactant composed of 99% polyoxyethylene-modified polydimethylsiloxane (Franz, J.E.et al, 1997, p.196). The Material Safety Data Sheet describes the formulation differently, as polyalkyleneoxide modified polydimethylsiloxane and nonionic surfactant, and states that this product contains organic silicone surfactant (Helena Chemical Co., 2001b).
The environmental fate of polydimethylsiloxane (PDMS) has been studied as a component of sludge applied to soils. More than 50% of the original amount was found to persist in subsoils as shallow as 2.5cm a year after application. PDMS was more persistent in colder climates than in warm climates (Singh, U.B.et al, 2000).
PDMS can be absorbed into the body by inhalation. No level of toxicity has been established for inhalation. The substance is also irritating to the eyes. This material is combustible (International Labor Organization, 2001).
Point Blank is a drift retardant composed of 34.3% polyacrylamide and 65.7% inert ingredients (unidentified). The MSDS for this product indicates that the inerts are eye and skin irritants. Chronic health hazards include the following: irritation of the respiratory tract resulting in asthma-like reactions with shortness of breath, wheezing or cough (Helena Chemical Co., 2001). Polyacrylamide can become a concern near water, as it breaks down to acrylamide, a known nerve toxin, which is highly water soluble and can be absorbed through all routes of exposure. Polyacrylamides can move through different soil types under varied conditions or bind to clay particles. Ammonium is a further degradation product of acrylamide and polyacrylamide (Smith, E.A. et al, 1997).
Thinvert is a drift retardant composed of 31.6% isoparaffinic hydrocarbons and 68.4% unidentified ingredients including water, emulsifiers and surfactants. All ingredients are on the Toxic Substances Control Act Inventory. The compound can be slightly irritating to eyes, and frequent or prolonged contact may irritate the skin and cause dermatitis. High vapor concentrations (greater than 700ppm at high temperatures) may cause headaches, dizziness, anaesthesia, drowsiness, nausea and mucous membrane irritation of eyes, nose, throat (Waldrum Specialties, 1992).
There are two tank mixes pre-formulated with Thinvert for spraying from a backpack by utility workers:
a. Arsenal, Escort and Krenite;
b. Arsenal, Escort and Accord
(C. Giguere, personal communication, Sept. 2 and Sept. 5, 2003).
38-F Drift Retardant
This product is composed of 32% polyacrylamide polymer and 68% unidentified ingredients (Sanitek Products, 1998). The Material Safety Data Sheet discloses that petroleum hydrocarbons are constitutents in this compound. Chronic health effects include damage to kidneys from prolonged inhalation of concentrated or heated vapors. Pre-existing allergies or disorders or skin or eyes can be aggravated by exposure (Sanitek Products, 1997a). The environmental fate and other health hazards will be similar to that of Point Blank Drift Retardant (see above).
41-A Drift Retardant
The principal chemical agents in 41-A are 27% polyacrylamide polymer, 3% polysaccharide polymer, and 70% unidentified ingredients (SANAG, 1996)
The MSDS states that the product contains trace levels (less than 270 parts per million) of acrylamide which is known to the State of California to cause cancer. In addition to irritation of eyes, skin and respiratory system, exposure to the product can aggravate pre-existing conditions of the eye or skin (Sanitek, 1997b). See POINT BLANK above for discussion of environmental fate and health hazards from metabolite acrylamide.
Hy-Grade consists of 100% petroleum oil! This product is used for spraying the base of trees and stump treatment, can be used year-round, and can be added to oil-soluble herbicides (CWC Chemical, Inc. n.d.).
Concerns for natural areas: The effects of petroleum oil on birds has been the object of study for about 30 years. As little as 1-10 microgram (1/1000 of a milligram) per Liter of some crude or refined oils applied to the surface of birds eggs could cause embryonic death or deformities and growth impairment. The toxicity was attributed to the blockage of pores over the surface of the shell, preventing absorption by the embryo of required oxygen. Topical application and immersion in the substance both had toxic effects on the birds. Parent birds can transfer enough oil on their feathers from affected areas to their eggs to cause toxic effects. Applications of 20 micrograms per Liter caused high mortality of embryos (Hoffman, D. and P.H. Albers, 1984).
Concerns for human health: Petroleum hydrocarbons are found in a wide variety of compounds and have a variety of toxic effects on humans, including affects on the nervous system, headaches, and dizziness (U.S. CDC. ATSDR, 1999). Their toxicity depends upon the components in the petroleum product.
The limits of human capability to predict or assess the total and long-term risks of combinations of chemicals--several herbicides, their inerts, metabolites, added drift retardants or surfactants and their metabolites-- to the health of citizens and to wildlife, ecosystems, water and air quality should be painfully apparent from the materials presented here, and taken very seriously. Such exposures present more severe and long-term risks for the unborn, infants and children, the aged, those with lowered immune systems and those whose lives are already compromised by chemical injury. The ability of the State of Vermont to monitor surface and groundwater contamination is severely limited. The Precautionary Principle tells us that when there is indication of harm, preventive action can and should be taken, even before all information can be gathered, to protect human health and the environment (Raffensperger, C. and J..A. Tickner, 1999). As non-toxic alternatives become available, the risks involved in using toxic chemicals become unjustifiable and must be avoided while accomplishing the necessary work of managing vegetation.
ALTERNATIVE METHODS OF WEED CONTROL
Myco-Tech is a biological control product developed in Canada by Myco-Forestis Corporation (LAssomption, Quebec) to control the growth of sprouts from cut stumps of deciduous species for use both in industrial forests and in utility and transmission rights-of-way. The technical active ingredient is a naturally occurring fungus, Chondrostereum purpureum strain HQ 1. The fungus, which occurs naturally on many hardwood trees in the temperate deciduous forest is cultured and formulated into a bio-degradable paste (Health Canada. PMRA, 2002).
Myco-Tech has been registered by Canadas Pesticide Management Regulatory Agency for uses in industrial forestry and utility ROWs east of the Rocky Mountains. (Myco-Forestis, 2002a) The product is presently involved in the US EPA Registration process, and that process is expected to conclude early in 2004 (N. Major, personal communication, December 9, 2003).
Myco-Tech has been used by Green Mountain Power Corporation in Duxbury since October 2001 under an experimental permit through the Vermont Department of Agriculture, Food and Markets. According to a GMP representative, Within only 1 year, Myco-Tech gives a soft and gentle change of vegetation return pattern. It will safe us at least 1 or 2 returns. Its amazing. (Myco-Forestis Corporation, 2003)
Since the purpose is to limit growth of vegetation in transmission and utility ROWs to 15 feet or less, low-growing species of vegetation are encouraged and trees that grow over 15 feet are cut. The cut stumps are treated within a half-hour with Myco-Tech paste, initiating a natural decomposition process and preventing the stump from resprouting into several new trees. The establishment of a maintenance cycle using Myco-Tech can increase the efficiency of mechanical cutting by 80 to 100%, depending upon the species treated (Myco-Forestis, 2002b), and reduce the need for cutting over a period of about 10 years (Times Argus, 2001). Presently, VELCOs ROW maintenance plan is on a 4 year cycle (VELCO, 1999).
Research shows that any infection of non-target trees is dependent upon the presence of recent wounding in those trees. Density of spores or drift is not the determining factor. The use of Myco-Tech is not likely to harm healthy non-target trees or change the naturally occurring fungus population. The fungus affects only woody-stemmed terrestrial plants; therefore, non-woody plants are not at risk from this product. Toxicology studies conducted by independent laboratories recognized by Health Canada and US EPA support the safety of this product to human health and the environment (Health Canada. PMRA, 2002, p.16).
Concerns for humans: While Myco-Tech contains the mycelium (vegetative part) of of the fungus rather than the spores, which tend to elicit more allergic reaction than the mycelium, most microorganisms contain substances that could elicit hypersensitivity reactions in humans. In this light, C. Purpureum HQ1 is considered to be a potential sensitizing agent (Health Canada. PMRA, 2002, p.8).
Myco-Tech and Risk Reduction
The use of Myco-Tech offers an alternative to traditional chemical management by increasing the efficacy of a brush cut operation and reducing the number of follow-up cutting operations required. In this way, Myco-Tech provides VELCO with an opportunity to greatly reduce their increasing dependence upon chemicals and their inherent risks (in compliance with 6VSA sec.1102) in their rights-of-way through natural communities, agricultural areas and residential neighborhoods. Myco-Tech is expected to receive USA EPA registration early in 2004, and thus to be available for general use in 2004 in the United States. The time is right for a non-toxic alternative for ROW vegetation management.
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